From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 407A5C2D0EF for ; Tue, 31 Mar 2020 07:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 176A820748 for ; Tue, 31 Mar 2020 07:36:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="uBqe5QH3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726397AbgCaHg2 (ORCPT ); Tue, 31 Mar 2020 03:36:28 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:24263 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726174AbgCaHg0 (ORCPT ); Tue, 31 Mar 2020 03:36:26 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1585640185; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=gb7Dm9+ZO/tL/05FL1gIARuoKSdDON1AWF1u2v9LPbA=; b=uBqe5QH3QWNWN0uq0LoCs7Pb422EWwLPMt2D6ESm0UWAObhqtvWlaUpObMdkHqro6TmYNdxN INNP2gPkEKFxEVlzIqLM0Pyww+q+dzedGD0Z98pCTtRnRypUegQz7ZAxSMn2PxeTtbFvUED9 i6iR6bRUclC64iu6XNHwF9rvVug= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e82f2ec.7f3b307aa340-smtp-out-n03; Tue, 31 Mar 2020 07:36:12 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id ACC4BC44788; Tue, 31 Mar 2020 07:36:12 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id 0830EC433F2; Tue, 31 Mar 2020 07:36:11 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 31 Mar 2020 13:06:11 +0530 From: Sai Prakash Ranjan To: Doug Anderson Cc: Robin Murphy , Will Deacon , Joerg Roedel , "list@263.net:IOMMU DRIVERS , Joerg Roedel ," , linux-arm-msm , LKML Subject: Re: [PATCH] iommu/arm-smmu: Demote error messages to debug in shutdown callback In-Reply-To: References: <20200327132852.10352-1-saiprakash.ranjan@codeaurora.org> <0023bc68-45fb-4e80-00c8-01fd0369243f@arm.com> <37db9a4d524aa4d7529ae47a8065c9e0@codeaurora.org> <5858bdac-b7f9-ac26-0c0d-c9653cef841d@arm.com> Message-ID: <890456524e2df548ba5d44752513a62c@codeaurora.org> X-Sender: saiprakash.ranjan@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On 2020-03-30 23:54, Doug Anderson wrote: > Hi, > > On Sat, Mar 28, 2020 at 12:35 AM Sai Prakash Ranjan > wrote: >> >> > Of course the fact that in practice we'll *always* see the warning >> > because there's no way to tear down the default DMA domains, and even >> > if all devices *have* been nicely quiesced there's no way to tell, is >> > certainly less than ideal. Like I say, it's not entirely clear-cut >> > either way... >> > >> >> Thanks for these examples, good to know these scenarios in case we >> come >> across these. >> However, if we see these error/warning messages appear everytime then >> what will be >> the credibility of these messages? We will just ignore these messages >> when >> these issues you mention actually appears because we see them >> everytime >> on >> reboot or shutdown. > > I would agree that if these messages are expected to be seen every > time, there's no way to fix them, and they're not indicative of any > problem then something should be done. Seeing something printed at > "dev_error" level with an exclamation point (!) at the end makes me > feel like this is something that needs immediate action on my part. > > If we really can't do better but feel that the messages need to be > there, at least make them dev_info and less scary like: > > arm-smmu 15000000.iommu: turning off; DMA should be quiesced before > now > > ...that would still give you a hint in the logs that if you saw a DMA > transaction after the message that it was a bug but also wouldn't > sound scary to someone who wasn't seeing any other problems. > We can do this if Robin is OK? -Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation